BTW, State has a widely-known bias toward being (sometimes) excessively cautious, leaving warnings up too long, being overly dismal about some countries, etc
I would take issue with State being excessively cautious. Actually, it is just the opposite. Pressure from Washington and the host government make it very difficult to issue such warnings. They have a major economic impact on the host country in terms of tourism and business. We use it as a lever in fact with the host government to get them to take various actions. For example, the Greeks have been lax about airport security. We have threatened to issue security warnings if they didn't tighten things up.
Travel warnings typically urge Americans to completely avoid visiting a country for "non-essential" reasons.
But you've illustrated my point: a travel warning against Greece (due to lax airport security) would have little bearing on beachgoers sitting in Mykonos. Nor would it account for the reality that travelers will spend only 30 minutes in any Greek airport, and the odds of having a problem might actually be quite miniscule.
When I say "excessively cautious", I mean there's a certainly lack of granularity in the warnings, and many people (myself included) think the British Foreign Office is a bit more incisive in its travel assessments (even though they also have an "essential travel" warning for Saudi right now).